A new cationic liposome encapsulating genetic material. A potential delivery system for polynucleotides

The endeavour to enhance gene therapy has led to increased research on the development of simple, efficient and safe delivery systems. This study deals with the use of an artificial cationic lipid on the encapsulation of genetic material in liposomes. The addition of a biologically degradable cationic phospholipid, dipalmitoyl-L-alpha-phosphatidylethanolamine covalently coupled to L-lysine, in a standard liposome formulation allowed us to obtain vesicles with high entrapment of various polynucleotides. Polynucleotide degradation by nucleases is markedly prevented by these liposomes. The preparations were stable in both culture medium and human plasma. This latter finding is consistent with the weak binding of plasma proteins on the liposome surface. The efficiency of this new delivery system was demonstrated in antiviral assays. Finally, these liposomes displayed a relatively low cellular toxicity. All these findings indicate that these cationic vesicles are very suitable for genetic material vehiculation.